Keyboard perforator



KEYBOARD PERFORATOR Filed June 30, 1955 2 Sheets-Sheet l FIG.I

ENTOR EDWARD LARSON Bf WM.

ATTORNEY Nov. 18, 1958 E. s. LARSON KEYBOARD PERFORATOR Filed June so, 1955 2 Sheets-Sheet 2 FIG. 2

INVENTOR EDWARD S. LARSON TORNEY United States Patent.

, 2,360,708 ARD- FQRA R Edward S. Larson, Chicago, IlL, assignor, by mesne as- The present invention relates, generally, to perforating appar'atu's and morejparticularly to keyboard perforators for the perforation of indicia'in a strip which fmaybe used for the automatic control of, a machine.

The present invention'has for itsmain object a simplifie d electromechanical clutch trip mechanism which will reduce the amount of key pressure required for release an better the key touch in other ways.

' Another object is to eliminate the mechanical nonrepeat mechanism froin the conventional trip offiinechanisrni A further object is to provide a diife'rential contact for positive nonrepeat action of the ke'yleVer. still further object is an electromechanical system which is operable on aminimum of current.

Thepresent invention is illustrated in'a keyboard perforator similar to that disclosed in Patent No.,2,0 19,"505 issued to A. H. Reiber on November 5, I935. The keyboard has'a bankof keys sir'nilarfto thatof a typewriter.

Each keylever' is operatively 'pbsitioned with'respect" to a grou of selector element's. Depression of each of the keylevers operates "the s'electorelemerits 'to' condition" a predetermined permutation of punches tobe operated. Also actuated by' thedepression of each keylev'er is a universal trip-01f mechanism which controls the one cycle operation of 'a power' driven means for actuating the permutatively selected punchesl Since the presentinvention is primarily concernedwithan improved trip-off mechanism, only so 'much of the keyboard" as'is necessary 'for" an uiider's tantlingmf' the invention will be "discussed.

For the sake of clarity, the reference numeralsjused to designate similar parts shall be the same as "thoseof the afore-mentidn'ed Reiber" patent which is incorporated "hereinby reference;

A better understanding of the invention may be had fro'mthe' following description taken in conjunction with the ac'companying drawings wherein:

Fig. l is-a partial perspective'view of a keyboard perforator embracing the features of the present'invention;

and 1 i Fig. 2 is a schematic view showing the present invention andthe wiring diagram associated therewith.

"Referring now to the drawings, wherein like reference numerals indicate the same part throughout=both views, and more particularly-to Fig. 1, thereis showna keyboard unit and a perforating unit, indicatedgenerally at 11 and 12, respectively, which are mounted on a common base 13. The keyboard unit 11 comprises a plurality of keys 15 and keylevers 14 as well as a space bar and lever (not shown). A power shaft 68 is driven by a gear 71 -on a constantly rotating motor 69anda gear 72 engaged therewith. Operation of the perforator 12 is powered the R'eiber patent.v Rotation of the collar 85 andthere'by the cam 42 is prevented by a blocking or stop lever 16 associated with one of two horizontal extensions 82 or 83 which are associated with slots on the collar 85. The

selection ofa permutation of punches by the keylevers 14 and the activation of the above-mentioned cyclebf operation by the keylevers is fully treated in the aforementioned Reiber patent.

Referring now to Fig. 2, the stop lever 16 is urged against a lever stop 17 by its spring 18,to be therebypd sitioned beneath the horizontal extension 82 of the collar 85 to prevent rotation of the collar 85. Anelectroma'g net 19 is p0sitionedrelat ive to theflblocking lev'erflfi so that energizationofthe magnet19 will attract: the'lever 16 and cause it to be rotated clockwise fabout"its 'pivot 21 out of the path of the horizontal" extension 82. When the lever 16 is moved out of its blocking -po'si tion, t'he collar 85 is permitteclf to rotate clockwise to 'ac tivate the punch actuator, as previously described. The electromagnet 19 has one side of its windingconnect'ed to a positive current source through'alead' 23. The other sideof the winding of the electromagnt *19-is connected through a lead 24 to the terminal'of a contact spring31, forming part of a spring pile-up 29. Thefcontact spring 31' is positioned to be engaged by a movable contact spring 32 which normally engages a fixed contact spring 33, but may be moved by auniversal'bar 36 from its normal position in engagement with the contact spring 33 to engagement with the contact spring 31. The universal bar 36 extends across beneath all-ofthe key levers14 and actuation of any one of the'keys 15, and consequent actuation of its associated key lever 14, will cause the universalbar 36 to be rocked abouta pivot 37 against the action of a restoring spring 46. i i

When the movable contact spring 32 is actuated by the universal bar-36 it will close a circuit fromIf-the-wiiiding' of the electromaghet 19 through the lead 24 and through a capacitor 34 and two leads 43 and 41 'tojthe negative side of the current source, thereby to cause a surge of current to be applied to the electromagnet 19 which is sutficiently strong=to energize the 'electromagriet 19 momentarily. i

In the event that it is desired to use the present apparatus with an alternating current source,-a capacitor"27 may be connected between the lead 23 and the lead 41 and a rectifier 26 may be connected in the lead 235etween the current source and the point at which thereapacitor 27 is connected to the lead 23. r i i j When the movable contact spring 32 is in its normal position as shown in the drawing (Fig. 2),-a resistor 28 will be connected across the capacitor 34, the capacitor but if the electromagnet 10 has beenoper'ated by moving themovable contact spring 32 from its normal position to engagement with contact spring 31, the-closure'gof key 38- will maintain the electromagncfw energized thereby to permit continuous rotation of the collai7f85.

Inthe event that the current source used is alternating current, the capacitor 27 will be maintained charged at all times, and'closureof the pair of contactsprings 31 and 32, and the consequent charging of .capac'itorp'34,

will result in a surge of current being fed to-I the electromagnet 19 to effect the same result as would be effected if the currentsource were direct current. As thecapaci- "tor 34 charges, the surge of current through Ithe electromagnet 19 will decay rapidly until it goes below the holding current value, at which time the magnet armaone will release, even though a key 15 is held depressed and contact springs 31 and 32 are closed. As a conse quence of this arrangement, even though key 15 is held depressed, the electromagnet 19 will release in time to limit the rotation of the collar 85 to one half of a revo- .luticn. 1

When the contact spring 32 moves to its normal position, as shown in Fig. 2, to close a circuit between it and contact spring 33, capacitor 34 will discharge through the resistor 28. By choosing a low value of resistor 28, the discharge process can be very rapid. However, the

- provision of the resistor 28 in the circuit shown will limit the discharge current to the point where the contact springs'32 and 33 will not be burned due to arcing between them.

If it is for any reason desirable, the resistor 39 may be i'educed t6 permit actuation of the magnet upon closing bf th'e switch 38.

The dotted portion of the circuit illustrated in Fig. 2 shows how the present invention may be adapted to remote control. The contact pile-up 61, capacitor 62, and resistor 63 correspond respectively to the parts 29, 34, and 28 of the circuit described above. The circuit may be operated by the contact lever 64. h I

When the keylever 15 is depressed by the operator,

I the universal bar 36 is rotated in a clockwise direction about its pivot 37 to close the circuit between contact spring 32 and contact spring 31 to complete the circuit irom one side of the current source, and lead 41 through the capacitor 34, closed contact springs32 and 31 and lead 24 to one side of the winding of the electromagnet 19 and through the electromagnet, lead 23 and rectifier 26 to the other side of the current source, to charge the capacitor 34. As the capacitor 34 charges, the charging current for the capacitor 34 passes'through the electromagnet 19. The charging current is of a sufiicient magnitude to activate the electromagnet 19. Activation of magnet 19 causes the blocking armature 16 to be rotated clockwise out of its blocking position to allow the collar 85 to be rotated to engage the positive clutch and thereby actuate the punch as described in the aforementioned Reiber patent.

The automatic release of the blocking aramture 16 before the collar 85 has completed a half revolution so as to block further rotation of collar 85 by cooperation of the blocking lever 16 and the projection 83 is accomplished as the capacitor 34 reaches its full charge. Short- .ly after the contacts 31 and 32 are closed the charging current of the capacitor 34 decays to a value below that of the holding current of the magnet 19 so that the blocking lever 16 is no longer attracted by the magnet 19 and is returned to its blocking position by the action of its spring 18.

An important feature of the present invention lies in the fact that the foregoing release action takes place while the keylever 14 is held down so as to keep contact :spring 32 in contact with contact spring 31. thereby elimimating the need for any additional anti-repeat mechanism. It should be further noted that once the capacitor 34 has been charged there is only inconsequential capacitor leakage current in the winding of electromagnet 19, and that inadvertent opening and closing of the contact between the contact springs 31 and 32 will have no effect on the mechanism. This feature eliminates the difficulty encountered when the contacts may be jarred through vibration of the machine. The gap between contacts on the contact springs 31 and 32 is of sufficient magnitude to allow for vibration without the contacts on contact springs 32 and 33 coming into contact.

When the keylever 15 is released, the universal bar 36 will be returned to its unoperated position by its spring 46. As the universal bar 36 returns to its rest position,

the contact spring 32 follows it, thereby opening the charging circuit and closing the discharge circuit of capacitor 34. Closing of the discharge circuit, causes the charge of capacitor 34 to be dissipated through the resistor 28. The presence of the resistor 28 prevents the burning of the contacts by a sudden high charge from the ca pacitor 34 when the contact on contact spring 32 en gages the contact on contact spring 33. I

When. the operator desires to automatically repeat a selected key, he operates the repeat button 38 which puts the line 44 and the resistor 39 into the circuit with the magnet 19. The resistor 39 has a resistance, value high enough so that the current through the circuit will be only large enough to hold the magnet 19 operated but will not be enough for initial operation. Thus, when the repeat lever is operated, nothing will happen to the system until a keylever is depressed. When the keylever is depressed while the repeat button is operated, the magnet 19 and blocking lever 16 will be operated as previously described. The repeat circuit will sustain a holding current in the magnet so that the collar and the cam 42 will continue to rotate so long as the repeat button 38 is op= a s The remote control circuit, shown dotted in Fig. 2, is operable in the same manner as the keylever circuit previously described and enables an operator to trip off the punch actuator from a remote station.

While the present invention is described in a particular embodiment, it isof course understood that the invention is capable of embodiment in widely varied forms without departure from the spirit and scope of this invention.

What is claimed is:

1. In a perforator, a punch actuator, ,an ar'rnatnfe ture means operable in its unattracted position to block operation of said actuator, an electromagnet associated with said armature means, means for supplying current to said electromagnet including a current source,- means ca necting one side of the current source to one eri'cl of the winding of the electromagnet, a parallel circuit in serles with the other side of the winding of the electromagnet and the other side of the current source, a resistor and a repeat contact connected in one arm ofsaid parallel eii'- cuit for limiting the current through said electroii'iagriet; and a capacitor and a key-operated contact connected in a second arm of said parallel circuit for supplying an actuating pulse to said electromagnet.

2. In a perforator, a rotating punch actuating means, an armature means operable in its unattracted position to prevent rotation of said actuating means, an electromagnet adapted to attract said armature when energized,'a normally open circuit for supplying current to said electromagn'et, including a current source, a capacitor arranged to be connected in series between said electromagnet and said current source for passing an operating current through said electromagnet, a first resistor in said circuit arranged to be connected in series with said ca pacitor for discharging said capacitor, a second resistor arranged to be selectively connected in said circuit parallel with said capacitor, and switching means for connecting said capacitor selectively either in series with said electromagnet or in series with said first resistor.

References Cited in the file of this patent UNITED STATES PATENTS Anderson Aug. 19, 1952 

